Sandwich-type Inorganic-Organic Hybrid Solids of Iso-polyvanadate Clusters and Decamethylcucurbit[5]uril

Three sandwich-type inorganic organic hybrid solids based on iso-polyvanadate cluster, {V4O12}(4-), {H2V6O18}(4-), or {H2V10O28}(4-), and decamethylcucurbit[5]-uril (Me10CB[5]) have been synthesized under hydrothermal conditions. In the structures of (NH4)(4)[(V4O12)center dot(Me10CB[5]@0.5H(2)O)(2)]center dot similar to 15H(2)O (1) and (NH4)(4)[(H2V10O28)center dot(Me10CB[5]@H2O)(2)]center dot similar to 16H(2)O (3), tetranuclear {V4O12}(4-) or decanuclear {H2V10O28}(4-) clusters are sandwiched by (NH4)(2)@Me10CB[5] closed molecular capsules, through hydrogen-bonding interactions, whereas compound 2, formulated as Li-4(H2O)(6)[(H2V6O18)center dot(Me10CB[5]@H2O)(2)]center dot similar to 14H(2)O, is built by hexanudear {H2V6O18}(4-) clusters that are covalently sandwiched by Li-2@Me10CB[5] half-open molecular capsules in a way similar to thoset of 1 and 3. Compounds 1-3 represent rare examples of sandwich-type polyoxometalate (POM)-based materials in which POM units are inserted at the inner sphere by either hydrogen or covalent bonds. Compound 2 has shown rational photocatalytic activity toward the degradation of methyl orange solutions under visible light.